This invention relates to copying or reproducing apparatus wherein electrostatic images are formed on a light sensitive surface with subsequent development of the latent images formed thereby and more particularly to an advanceable photoreceptor construction for use therein.
In the process of xerography and other processes wherein latent electrostatic images are formed by electrostatic charges on a light sensitive substrate material, the image of an original to be copied or reproduced is typically recorded in the form of latent electrostatic images upon a photosensitive or other charge-retentive member with subsequent rendering of the latent image visible by the application of electroscopic marking particles, commonly referred to as toner. The latent images may also be formed on the photosensitive member by exposing a uniformly charged photosensitive member to an optical image corresponding to intelligence generated by electronic means.
In the earliest developments of the technology, the photosensitive member was constructed in the form of a drum which was supported for rotation such that a uniform electrostatic charge could be first placed on the photosensitive member with subsequent exposure of a light image in order to discharge portions of the photosensitive member in accordance with the light images and then the image portion of the photosensitive member is moved past a development station where the electrostatic images were rendered visible by means of application of toner particles which would electrostatically adhere to the photosensitive member in the areas thereof still containing electrostatic charges.
Subsequent developments, in the photosensitive member area, designed to improve the performance (i.e. less maintenance, etc.) of the reproducing apparatus led to the development of what has become known as an advanceable photoreceptor. The advanceable photoreceptor comprises a web of photosensitive or photoreceptor material the bulk of which is supported internally of a hollow drum while a portion thereof is trained over the outer surface of the drum for employmemt in the image forming process. The bulk of the web is supported internally of the drum by a supply roll containing unused photosensitive material and a takeup roll which contains photoreceptor material already used. In operation, the portion of photosensitive material entrained on the surface of the drum is utilized until such time as the effectiveness thereof for such purposes begins to diminish or becomes unsuitable for such purposes. At that time, the transport mechanism comprising the takeup reel and supply reel is actuated either automatically or manually in order to move the used photoreceptor material onto the takeup reel and move unused photoreceptor material from the supply reel to the surface of the hollow drum. Obviously, the foregoing construction is limited as to the capacity of photoreceptor material that can be stored internally of the drum for a given sized drum.
Accordingly, a primary object of this invention is to provide an improved copier apparatus.
Another object of this invention is to provide, in a xerographic copier apparatus, an improved advanceable photoreceptor construction.
Still another object of this invention is to provide, in a xerographic copier or reproducing apparatus, a photoreceptor construction in the form of an advanceable photoreceptor structure which provides greater capacity than structures of the prior art.